1. Field of the Invention
The present invention generally concerns the demand reporting by each of a great multiplicity of electricity-using sites of (i) the instantaneous rate(s) of electricity usage (i.e., watts) at the site, and/or (ii) the total electricity usage during a period (i.e., watt-hours) by the site. The reporting is in response to radio requests from a central reporting station that may, according to the distance of the interrogated site, be relayed through each of a number of like sites.
The present invention also concerns demand-reporting radio-linked radio-relay-communicating electronic wattmeters that can be arrayed in great numbers over large areas so as to monitor and to report upon demand by radio instantaneous and/or historical electricity usage by homes and by businesses within the area.
2. Description of the Prior Art
2.1 General Requirement Circa 1990 for An Electronic Power Meter
U.S. electrical utilities have desired for some time power meter features and capabilities that the traditional electromechanical power meter cannot provide. However, these desires have not as of yet, circa 1995, been considered sufficient justification for a complete one-for-one replacement of existing residential power meters.
Without the market scale which would be dictated only by wholesale replacement of existing residential power meters, electronic meters have been relegated to niche markets. Now (circa 1995), however, electrical utilities face the new requirement of wheeling. With the advent of Wheeling, utilities are willing to consider a complete replacement of the existing electromechanical meters. It is desired that a more powerful electronic meter would be produced at a price comparable to, or less than, the existing electromechanical meter.
Utilities throughout the United States recognize that Wheeling is rapidly becoming a reality and the resulting competition will dictate the adoption and utilization of a new metering technology. Many new and interesting metering products are becoming available, but to date these products have targeted small niche markets. The price and longevity of the electromechanical meters have prevented direct competition for the large residential market. However, wheeling [defined and further discussed in the fourth paragraph hereinafter] now provides the opportunity to upset this long-standing impasse.
The requirements for electric utility metering in the United States are driven by the customer. There is a general concern for customer satisfaction in the utility industry which is being driven to some degree, circa 1995, by the prospect of wheeling. The specific areas where utilities are interested in improving their customer interface are in offering (i) variable rates for load management, (ii) direct load curtailment, (iii) time of use (TOU) information, (iv) security, and revenue protection, (v) reduced expenses in meter reading, and (vi) customer interactive communications.
At the present time there appear to be an abundance of reasons for the U.S. utility industry to anticipate changes and prepare to operate competitively in a significantly different business environment. Some of the factors that contribute to the changes are include: (i) the present and long term United States economics trend of expansion, (ii) wheeling, (iii) electric vehicles, and (iv) new technology.
Detailed discourse regarding the US economy is beyond the scope of this disclosure. However, U.S. electric utilities have been seriously affected in the past by varying interest rates. Power generation expansion that requires borrowed capital could put a utility at risk.
Wheeling became a reality when the Public Utility Regulatory Policies Act of 1978 (PURPA) amended the Federal Power Act and gave the Federal Energy Regulatory Commission (FERC) expanded responsibilities for the encouragement of co-generation and small power production using alternative energy technologies. See Electric Power Wheeling and Dealing, Technological Considerations for increasing Competition; Congress of the United States Office of Technology Assessment PP 55. The goals of PURPA were to advance: 1) conservation of electric energy, 2) increased efficiency in electric power production, and 3) achievement of equitable retail rates for consumers. This was advanced in large part by requiring utilities to interconnect with and buy power from co-generators and small power producers that met standards established by FERC. This was the first major Federal move to open up electricity markets to non-utilities.
There have been other amendments to the Act of 1978 and all the utilities that were contacted in our market survey are preparing for the added competition that the act allows. In this relative new competitive environment, the energy will be billed to the utility that can provide the best service at the lowest cost. Better service can be accomplished by: 1) instantaneous readouts for shut-offs, turn-ons, verification, etc. 2) TOU (time of use) profiles which will allow rate change allowances, 3) faster and more accurate billing and 4) demand load control. Finally, the lower cost will result from: 1) manual meter reading elimination, 2) load leveling, and 3) improved customer relations.
Another government mandate that is destined to impact the utility industry is electric vehicles. Air pollution has prompted the State of California to establish quotas for non-polluting (electric) vehicles in the Los Angeles area. Not only will the use of electric vehicles increase the need for electrical energy, but a new metering concept will be required. At least one utility is currently buying communications equipment so that each electric vehicle can have it's own individual power meter. This allows the utility company to appropriately charge the vehicle owner irrespective of where the vehicle batteries are recharged. The magnitude of the added energy usage requirement is clearly brought into perspective in realizing that the energy requirements for an electric vehicle would about parallel the usage of a typical residence.
It is interesting and important to note that the DRM system proposed here would exactly satisfy the electric vehicle metering requirements. A readout could be accomplished at any time when the vehicle is domiciled at a designated location. Alternatively a search and read program could be implemented to perform a readout anywhere in the utility service area.
A number of advancements in new technology can now provide the basis for a significantly different residential power meter. Microprocessors have been developed for large volume applications, particularly for the automotive industry, and RF integrated circuits have been developed for large volume application such as commercial radios, pagers and portable telephones. The large volume is the ingredient that dictates the economics, and these particular components are directly applicable to the power meter application.
2.1 Specific Objectives of a New Electronic Power Meter
An increased-capability electronic power meter should be provided at a price comparable to the existing residential electromechanical power meter. However, capabilities will be enhanced. The desired new capabilities include the following:
A new electronic power meter would desirably offer built-in two-way RF communications for automatic remote meter reading.
It would retain hourly time-of-use (TOU) measurements for 30 days. Alternatively, it would retain TOU measurements every 21/2 minutes for 2 hours,
A new electronic power meter would desirably offer record the time of, and send an alarm, at the onset of any tampering so as to help preclude energy theft.
It would desirably provide a remote display for customer communications.
Finally, a new electronic power meter would desirably provide output control for load curtailment.
The new electronic power meter should have an operational life of at least 15 years with a failure rate of less than 1% per year, an normally much, much less. Electronic devices can easily achieve this stringent operational requirement. A new electronic power meter would in particular be designed with proper derating and overall conservatism to guarantee the prescribed long life, target costs and performance.